Field of the Invention
The present invention relates to input devices and the like configured to receive inputs entered using a pen and the like through sheets such as paper placed on a detection surface.
Description of the Related Art
There are input devices configured to detect the pressure of a writing material by a pad-like touch panel laid immediately under paper to write on to receive inputs of character information (refer to JP 2006-172230 A, for example).
When an input entered by a writing material such as a pen is received via sheets placed on a touch panel, the pressure applied by the writing material is dispersed by the sheets and there is thus a difference between the area (width and thickness) of the pen nib of the writing material and the area of the pen nib detected by the touch panel via the sheets. For example, when a single thin sheet 201 is placed on a touch panel 200 as shown in FIG. 13A, the difference between the area S1 of a pen nib of a writing material 202 and the area S2 of the pen nib detected by the touch panel 200 via the sheet 201 is small, which is not often a problem. When, however, multiple sheets 203 are placed or a sheet 203 is thick or hard as shown in FIG. 13B, the difference between the area S1 of the pen nib of the writing material 202 and the area S3 of the pen nib detected by the touch panel 200 is larger, which may result in that a character or the like is input with such a thickness that is not intended by the user.
Furthermore, the area S3 of the pen nib detected when an input is entered by the pen 202 via multiple sheets 203 becomes close to the area (thickness of finger) S4 detected by the touch panel 200 when input is entered by a finger 204 via a single sheet (see FIG. 13C). Thus, if whether an input is entered by a finger or a pen is determined on the basis of the detected size of the area, an input entered by a pen may be erroneously detected to be an input entered by a finger.